An Egyptian court confirmed death sentences for Muslim Brotherhood leader Mohamed Badie and 13 other senior members of the Islamist organisation on Saturday and jailed a US-Egyptian citizen for life for supporting the group.

The ruling by Egypt’s Grand Mufti, the country's senior Sunni authority, ratified the death sentences handed to Badie and other leading Brotherhood figures in a court decision last month.

They were accused of inciting chaos and violence during Islamist protests in the country in the wake of the army coup that ousted then-president Mohammed Morsi, a senior Brotherhood member.

The court also sentenced US-Egyptian citizen Mohamed Soltan to life in jail for supporting the group and transmitting false news. Soltan is the son of Brotherhood preacher Salah Soltan, who was among those sentenced to death on Saturday.

Another 23 detained defendants were handed life sentences.

The sentences can be appealed before Egypt’s highest civilian court in a process that could take years to reach a final verdict. The defendants were among thousands detained after the ousting of Morsi in 2013.

Egypt’s mass trials of Brotherhood supporters have drawn international criticism of the country’s judicial system.

President Abdel Fattah al-Sisi, who as army chief toppled Morsi following mass street protests, describes the Brotherhood as a major security threat. The Brotherhood says it is committed to peaceful activism and had nothing to do with recent Islamist militant violence in the country.